Increasingly, housings are being used for receiving electrical or electronic structural units and assemblies, in which the individual assemblies, which are also usable for other apparatus of the manufacturer, are combined in a respectively desired manner. Standard housings are particularly suited for this, e.g., 19" assembly carriers, since, due to standardization, a plurality of assemblies of various manufacturers are combined with respect to their mechanical structure.
One assembly, which is provided in every electrical or electronic apparatus, is the power pack. This type of power pack is furnished by the manufacturers in a plurality of connecting values (output voltages, power wattage) and corresponds in its outer design to the above-mentioned standards and consequently can be used in every standard housing.
Furthermore, for the standard housing of one manufacturer, front plates or rear walls of another manufacturer can be used, since these housing measurements are standard.
Upon using power pack inserts in the housings, the problem occurs that a substantial part of the heat due to energy loss generated in the entire apparatus originates from the power pack. This heat loss, together with the heat loss of the remaining assemblies, heats up the inner space of the housing, which, on the one hand, requires special cooling measures, and on the other hand, reduces the life span of the assembly parts. Furthermore, special compensation measures have to be taken so that the temperature variations of the individual structural parts are adapted to the often rather high housing inner temperatures.
As an attempted solution of this thermal problem one sometimes provides the power pack part insert with a separate ventilator which is to carry off the heat generated by the power pack towards the rear out of the housing. In this case, a special rear wall with a ventilator unit has to be provided which renders possible the free ventilation of the power pack.
Furthermore, often a ventilator is provided for cooling the electronic assemblies (apart from the power pack) which ventilator again has to be mounted on the rear wall. If the finished apparatus is to be operated in dusty surroundings, then extensive measures have to be taken (filters, etc.), to keep the housing inner space dust-free and nevertheless to secure a sufficient heat discharge.
Finally the power pack, in particular, when it generates large output power, uses up a large part of the housing inner space which consequently no longer is available for receiving the electronic assemblies.
From Great Britain Patent No. 20 45 006 a rear wall for such a housing for electronic assemblies is known which is equipped with cooling fins and on which the semiconductors of the power pack, which generate the heat, are directly screwed on the housing rear wall. Thus the power pack is not interchangeable in different housings, so that a certain power pack (with special voltage, currents) is not always equivalent to or usable with another housing rear wall.
From German-OS Patent No. 24 36 586 a modular constructed housing has been known in which housing parts can be assembled into a unit. The housing parts are so designed that there is always a flush outer rear wall. The major advantage of this arrangement consists in that the individual structural units, which are contained in the housing modules, are protected from one another.
From German-OS Patent No. 29 36 499 a housing has been known where the power pack plug-inboard is insertible parallel to the housing rear wall similar to a mother plate. The housing rear wall itself is designed as a plane surface in the usual manner.
From German-Gm Patent No. 19 31 928 a housing has been known in which cross air ventilation is arranged in the housing, which generates, via ventilators, an air flow parallel with and along the housing rear wall, in order thus to cool the structural elements arranged in the housing interior. The rear wall itself is designed in the usual manner. Further ventilation devices for a housing have been known from German-OS Patent No. 27 44 664.
Starting with the prior art, it is an objective of the present invention to develop a rear wall for a housing in a manner that an increased variability is achieved in the electrical and thermal design of the power pack which simultaneously uses less space and has improved heat discharge without substantial cost increase.
This problem is solved by the combination of elements stated in the claims.